function Game(el) {
  //保存地图对象
  this.el = document.querySelector(el);
  //地图
  this.map = new Map(this.el);
  this.map.create();
  //食物
  this.food = new Food(this.el);
  this.food.create();
  //snake🐍
  this.snake = new Snake(this.el);
  this.snake.create();
}
Game.prototype.start = function() {
  t = setInterval(() => {
    this.snake.move();
    let snakeX = this.snake.snakeObj[0].x * 20;
    let snakeY = this.snake.snakeObj[0].y * 20;
    let foodX = this.food.foodX;
    let foodY = this.food.foodY;
    if (snakeX == foodX && snakeY == foodY) {
      let last = this.snake.snakeObj[this.snake.snakeObj.length - 1];
      this.snake.snakeObj.push({
        x: last.x,
        y: last.y,
        color: last.color,
        el: null
      });
      this.snake.create();
      this.food.move();
    }
  }, 200);
  document.addEventListener("keydown", e => {
    e = e || window.event;
    switch (e.keyCode) {
      case 38:
        this.snake.direction = "top";
        break;
      case 40:
        this.snake.direction = "bottom";
        break;
      case 37:
        if (this.snake.direction == "right") {
          alert("Game Over");
        }
        this.snake.direction = "left";
        break;
      case 39:
        this.snake.direction = "right";
        break;
      default:
        break;
    }
  });
};
Game.prototype.stop = function() {
  setInterval(() => {
    clearInterval(t);
    // alert("游戏结束");
  });
};
